Scissors jack

ABSTRACT

A scissors jack, constructed in accordance with the present invention, is disclosed herein and generally includes a base supporting a lower link assembly, an intermediate link assembly and an upper link assembly, all of which cooperate with each other and with a screw assembly for driving a load lifting element between a lowered or load releasing position and a raised or load lifting position.

United States Patent [1 1 Morgan et al.

SCISSORS JACK [75] Inventors: George H. Morgan, South Bend,

Ind.; Robert Harlan Nehrig, I Stevensville, Mich.

[73] Assignee: Auto Specialties Manufacturing Company, St. Joseph, Mich. [22] Filed: Sept. 18, 1970 [21] Appl. No.: 73,293

[52] U.S. Cl. 254/1-22 [51] Int. Cl 366i 3/22 [58] Field of Search 254/122, 124, 126; 187/18 [56] References Cited UNITED STATES PATENTS 3,614,065 10/1971 Adamski et a1 254/122 1,429,945 9/1922 Hern 254/122 1,709,746 4/1929 Schwerin 254/122 1 June 26, 1973 2,758,816 8/1956 Pickard et a1 254/126 2,920,871 1/1960 Kolodin 254/122 FOREIGN PATENTS 0R APPLICATIONS 563,304 11/1932 Germany 254/122 Primary Examiner-Othell M. Simpson Att0rneyOlson, Trexler, Wolters and Bushnell [57] ABSTRACT A scissors jack, constructed in accordance with the present invention, is disclosed herein and generally includes a base supporting a lower link assembly, an intermediate link assembly and an upper link assembly, all of which cooperate with each other and with a screw assembly for driving a load lifting element between a lowered or load releasing position and a raised or load lifting position.

10 Claims, 9 Drawing Figures PMENIEBmzs mm 3.741. 524

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INVENTORS 394/ GEORGE H. MORGAN 34 ROBERT HARLAN NEHRIG 35w J /NVZWW,

SCISSORS JACK SUMMARY OF THE INVENTION The present invention relates generally to lifting jacks and more particularly to scissors type lifting jacks.

DISTINCTIONS OVER THE PRIOR ART AND OBJECTS A typical scissors jack of the general type disclosed and claimed herein is known in the art and includes a load lifting element supported by a base and moved vertically between an upper load lifting position and lower load releasing position by a plurality of interconnecting linking elements which pivotably move relative to each other. Because of the enormous load generally supported and moved by this type of jack, the base and linking elements thereof have been generally constructed of steel. This, of course, not only makes such a jack extremely expensive to manufacture, but also quite heavy and inconvenient to move around. To further add to its manufacturing expense, this type of jack, due to its scissors type action, requires that all of its linking elements be-of different shapes, which in turn necessitates the use of a large amount of highly expensive stamping equipment.

Accordingly, an important object of the present invention is to provide a new and improved scissors jack which is both economical to manufacture and relatively light in weight as compared to those scissors jacks of the prior art.

Another object of the present invention is to provide a new and improved scissors jack which, in addition to being economical to'manufacture and light in weight, is reliable in use.

Still another object of the present invention is to provide a new and improved scissors jack which utilizes a minimum number of different types of components.

These and other objects and features of the invention will become more apparent from a reading of the following descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a front elevational view of a scissors jack constructed in accordance with the present invention, the jack being shownv in its completely raised or load lifting position;

FIG. 2 is a side elevational and partially broken away view of the scissors jack, as illustrated in FIG. 1;

FIG. 3 is a front elevational view of the scissors jack of FIG. 1, the jack being shown in its completely lowered or load releasing position;

FIG. 4 is a plan view of the scissors jack, as illustrated in FIG. 3;

FIG. 5 is a plan view of the base used with the scissors jack of FIG. 1;

FIG. 6 is a perspective view of a lower link or channel used with the scissors jack of FIG. 1;

FIG. 7 is a side sectional view taken generally along line 7-7 in FIG. 3; v

FIG. 8 is a perspective view of an upper link or channel used with the scissors jack of FIG. 1; and

FIG. 9 is a vertical sectional view taken generally along line 9-9 in FIG. 1.

DETAILED DESCRIPTION Turning now to the drawings wherein like components are designated by like reference numerals throughout the various figures, a scissors jack, constructed in accordance with the present invention, is generally designated by the reference numeral 10, as illustrated in FIG. 1. The jack includes a base 12 supporting a lower link assembly 14, an intermediate link assembly 16 and an upper link assembly 18, all of which cooperate with each other and with a screw assembly 20 for driving a load-lifting element 22 between a lowered or load-releasing position, as illustrated in FIGS. 3 and 4, and a raised or load-lifting position, as illustrated in FIGS. 1 and 2. As will be seen hereinafter, the base 12, linking assemblies l4, l6 and 18, loadlifting element 22 and a portion of screw assembly 20 are constructed entirely of relatively inexpensive and thin stamped sheet metal which not only reduces the over-all expense in manufacturing the scissors jack, as well as increasing the dimensional accuracy thereof, but also reduces the weight thereof, so that the jack may be easily moved from one location to another. In addition, there is a reduction in the gross vehicle weight which, over the lifetime of the vehicle is not insignificant.

Turning now to a detailed description of base 12, attention is directed to FIG. 5 where the base is shown to include a substantially flat and horizontally extending .rectangular bottom support or base portion 24 which fans out at opposite transverse edges so as to form additional keystone shaped area portions 26 for aiding in supporting the scissors jack. Stamped out, or otherwise formed indents 28 are provided at, opposite corners of area portions 26 and extend downwardly therefrom.

. The indents act as feet type ground supports for the base, so that the latter may rest slightly above ground and thereby be unaffected by small bits of gravel or other types of solid material which might be located thereat.

A pair of upwardly extending side walls or flanges 30 and 31, which are formed with opposite edges of base portion 24 and adjoining area portions 26, aid insupporting lower link assembly 14, as will be seen hereinafter. In addition, two laterally spaced pairs of spaced apart and upwardly extending tabs or support flanges 32, 33 and 35, 37 arestamped out or otherwise formed from base portion 24 and are positioned slightly inwardly from opposite side walls 30 and 31, as illustrated best in FIG. 5. As will be seen hereinafter, these tabs or support flanges, along with side walls 30 and 31 aid in pivotally'supporting lower link assembly 14.

Base 12, which as stated above is preferably constructed of inexpensive, thin and light weight sheet metal, is bent and stamped or otherwise formed into the aforementioned shape so as to provide an integral unit.

Returning to FIG. 1, in conjunction with FIG. 6, lower link assembly 14 is shown to include two identical lower links 34 and 34awhich, like base 12, are

stamped out or otherwise formed into integral units cal, only link 34 will be described in detail, like parts of the two links being designated by like reference numetals with the suffix a designating those parts of link 34a. With this in mind, attention is directed to FIG. 6

which shows the lower link 34 to include spaced apart elongated and substantially rectangular side portions 36 and 39 which are joined at common longitudinal edges by a rectangular connecting flange 38. The lower transverse edge of each of the side portions 36 and,39 is formed with respective interconnecting teeth 40 and 41 which extend partially up the adjacent longitudinal edge of the side portion. In addition, the remaining free longitudinal edge of each of these side portions includes an outwardly flaring flange 42 and 43, respectively, formed therewith for adding strength to the over-all link or channel 34.

As noted in FIG. 2, the lower teeth configurated ends 40 and 41 of lower link or channel 34 are positioned within the laterally aligned openings formed between the side walls and 31 and respective adjacent tabs or support flanges 32 and 33 of base 12. The teeth configurated ends 40 and 41 are pivotally supported about the longitudinal axis of an elongated cylindrical pivot pin 44 which extends through aligned apertures 46 and 47 in the bottom of side portions 36 and 39 and cooperating apertures in sidewalls 30 and 31 of base 12. In addition, the pivot pin rests slightly above cooperating cleaver type notches 48 and 49 provided in the top edges of respective tabs or support flanges 32 and 33, as illustrated best in FIG. 3. The notches are shaped so that the amount of lateral pin clearance, that is the distance between the pin and the sides of the notches, is greater than the vertical clearance, that is, the distance between the pin and the bottom of the notches. In this manner, the pin easily may be assembled to the remainder of the jack without interfering with the tabs 32 and 33. On the other hand, any appreciable deflection of the pivot pin under load is restrained by the bottom of the notches which upon engaging the pin adds further support thereto. The tabs are locked in place by a cylindrical tubular spacer 51, through which the pivot pin is inserted. The pin is headed on one end and preferably staked on the other, as viewed in FIG. 2, for locking the same in place.

In like manner, the lower link or channel 34a is positioned within laterally spaced openings formed by the side-walls 30 and 31 and respective adjacent tabs or support flanges 35 and 37, and are pivotally mounted for rotation about the longitudinal axis of a cylindrical elongated pivot pin 44a which extends through cooperating apertures in the bottom of side portions 39a and 36a and sidewalls 30 and 31, similar cleaver type notches 48a and 49a being provided just below the pin for additional support thereof. A cylindrical tubular spacer 51a is provided around pivot pin 44a, between tabs 35 and 37 for locking the latter in place.

It should be noted that the right-hand tabs or support I flanges 32 and 33, as viewed in FIG. I, extend a slight distance higher than the left-hand tabs or support flanges 35 and 37, so that the interconnecting teeth 40 and 41 of lower link 34, which are positioned in confronting relationship with teeth 4la and 40a, engage or otherwise mesh with the aligned interconnecting teeth 41a and 40a oflower link or channel 34a. In this manner, as the link 34a is pivotally moved about the longitudinal axis of pivot pin 44a, the lower link 34 is caused to pivotally move about its pivot pin 44 in an opposite direction.

It is to be understood that while cleaver type notches 48, 48a, 49 and 49a are provided a slight distance below the respective pivot pins 44 and 44a,

semi-cylindrical notches may be provided and positioned in constant engagement with the pivot pins. In addition, the taps 32 and 35 may be positioned sufficiently close to tabs 33 and 37 respectively so as to eliminate spacers 51 and 51a.

Attention is now directed to a description of the intermediate link assembly 16 which comprises identical link pairs and 50a which, like lower links 34 and 34a, will be designated by like reference numerals, like components of the left-hand link pair 50a, as viewed in FIG. 2, including the suffix letter a to distinguish those components from like components of link pair 50.

As seen in FIG. 1, link pair 50a includes two identical elongated and substantially rectangular links or connecting arms 52a and 54a which are preferably constructed of light weight and inexpensive sheet metal and stamped or otherwise formed into integral units. The lower ends of links or connecting arms 52a and 54a are positioned adjacent the inside top surfaces of aligned side portions 39a and 36, respectively, where they are mounted for pivotal movement about the longitudinal axis of respective elongated and cylindrical pivot pins 56 and 58. These pivot pins, like pivot pins 44 and 44a, are headed at common ends but extend a substantially shorter distance, through cooperating apertures in side portion 39a and adjoining link 52a and side portion 36 and adjoining link 54a, and thereafter terminate in a manner to be described hereinafter (FIG. 4). The lower ends of links 52 and 54 of link pair 50 are positioned adjacent the inside top surfaces ofthe aligned side portions 36a and 39, respectively, where they are mounted for pivotal movement about the longitudinal axis of respective elongated and cylindrical pivot pins 57 (FIG. 7) and 59 (FIG. 2). Like pins 56 and 58, these pins are headed at common ends and extend through cooperating apertures in side portions 36a and adjoining link 52 and side portion 39 and adjoining link 54, (FIG. 4).

The upper link assembly 18 includes two elongated and substantially U-shaped identical links or channels 60 and 60 a which, like the links of lower link assembly 14 and intermediate link assembly 16, are constructed of light weight and inexpensive sheet metal which are stamped or otherwise formed into integral units. Like the above-described identical components, the components of links or channels 60 and 60a will be designated by the same reference numeral, those identical components of link 60a being distinguished from like components of link 60 by the utilization of suffix letter a.

Turning to FIG. 8, link or channel 60a is shown in perspective view to include two laterally spaced and aligned elongated and substantially rectangular side portions 62a and 64a which are joined at common longitudinal edges by a connecting flange 66a. In order to stiffen or otherwise add strength to the link 60a, a flange 68a is formed with the otherwise free edge of side portion 62a and extends inwardly therefrom.

The lower external surfaces of side portions 62a and 64a are positioned adjacent the upper inner surfaces of respective links or connecting arms 54a and 54, all of which include aligned apertures for receiving an elongated cylindrical pivot pin 70. In this manner, both the link or channel 60a and links or connecting arms 54a and 54 are mounted for pivotal movement about the longitudinal axis of the pivot pin 70. In a similar manner, the lower ends of the side portions 62 and 64 of link or channel 60 are positioned adjacent the inner top surfaces of respective links or connecting arms 52 and 52a, and include aligned apertures for receiving an elongated cylindrical pivot pin 72 for pivotal movement about the longitudinal axis of the pivot pin. As noted in FIG. 1, the links or channels 60 and 60a are positioned so that they open towards each other.

It should be noted, as illustrated in FIGS. 1 and 2, that links or connecting arms 52 and 54 and 52a and 54a are respectively interconnected substantially in the longitudinal middle thereof by an elongated cylindrical pivot pin 74 extending through common apertures therein, so that the links or connecting arms 52 and 52a move in a scissors type fashion relative to respective links or connecting arms 54 and 54a. Link pins 50 and 50a are laterally spaced apart by tubular spacer 75 circumscribing pin 74.

The top ends of links or channels 60 and 60a are pivotally mounted together by a pivot pin 76 extending through aligned apertures therein in the similar manner described with respect to the previous pivot pins. As illustrated in FIG. 9, the link or channel 60 is staggered or spaced slightly to the left relative to the link or channel 60a, so that side portion 62 of link 60 rests adjacent the inner surface of side portion 64a of link 60a. In the same manner, side portion 64 of link 60 rests adjacent the external surface of the side portion 62a of link 60a. In this way, the two links may pivotally move inward relative to each other, as will be seen hereinafter.

As seen in FIG. 9, the load-lifting element 22, which like the other components of scissors jack 10 is constructed of an inexpensive light weight sheet metal and stamped or otherwise formed into an integral unit, is fashioned as a substantially U-shaped element having inwardly extending strengthening flanges 78 formed with the free edges of the elements upwardly extending legs. The load lifting element is positioned between the links or channels 60 and 60a, as illustrated in FIG. 9, and includes cooperating apertures in its upwardly extending legs for receiving the pivot pin 76 for pivotal rotation relative to both of the links or channels 60 and FIG. I. The screw assembly includes a pair of substan 4 tially U-shaped brackets 80 and 82 which are constructed of light weight and inexpensive sheet metal and stamped or otherwise formed into integral units. Both of the brackets include outwardly extending flanges 84 and 86, respectively, formed with the otherwise free lateral edges of the base or leg-connecting portions of brackets 80 and 82 for providing added strength thereto. In addition, each of the brackets 80 and 82 is reinforced at points between the legs and base or leg-connecting portions by inwardly stamped angled flanges 88 and 90, respectively, as illustrated best in FIG. 4. In addition, the bracket 80 includes similarly angled and stamped flanges 92 positioned at a point where the flanges 84 join the base or leg connecting portion of the bracket. In this manner, bracket 80, which as will be apparent hereinafter withstands greater stress than that of bracket 82, is given additional support strength.

The bracket 80 is positioned so that one leg thereof extends between the side portion 36 of lower link or channel 34 and link or connecting arm 540, while the other leg thereof is positioned between the other side portion 39 of lower link or channel 34 and link or connecting arm 54, as illustrated best in FIG. 4. The brackets legs include respective aligned apertures for receiv-,

ing respective pivot pins 58 and 59 where the pivot pins terminate as illustrated in FIG. 4. In this manner, the lower link 34 and links or connecting arms 54 and 54a are allowed to pivotally move relative to the bracket.

Bracket 82 has its legs positioned adjacent the inner surfaces of links or connecting arms 52 and 52a and, like bracket 80, is connected for relative pivotal movement thereat by pivot pins 56 and 57.

The base or leg-connecting portions of each of the brackets and 82 includes an aperture extending therethrough for receiving the cylindrically elongated and threaded body portion 94 of a screw element 96, as illustrated best in FIG. 4. The right-hand end of the screw element, as viewed in FIGS. 1 and 4, includes a screw head 98 which is provided for receiving a cooperating tool for rotating the screw about the longitudinal axis of body portion 94, for reasons to be described hereinafter. A plurality of annular washer bearings 100 are provided around the screw elements body portion 94 between screw head 98 and bracket 80 for facilitation of rotational movement of the screw element relative to the bracket, the washers 100 being positioned within the flange 84 of the bracket.

Longitudinal movement of the screw element to the right, as viewed in FIG. 4, relative to bracket 80 is prohibited by a stopper portion 102 which is in the form of a radially outwardly extension of body portion 94 of the screw element. Specifically, in the event that the screw element 96 tries to move to the right relative to bracket 80, as viewed in FIGS. 1 and 4, the stopper portion 102, which is diametrically larger than the aperture provided in the base or leg-connecting portion of bracket 80, will prevent such movement.

Looking at the left-hand end of screw element 96, as viewed in FIG. 4, attention is directed to a threaded nut 104 which is welded or otherwise rigidly secured to the inner surface of the base or leg-connecting portion of bracket 82 and which is positioned for rotatably and threadably receiving the free end of the screw element. As will be seen hereinafter, upon rotation of the screw element through threaded nut 104, the entire bracket 82 will move longitudinally along the screw element.

With the scissors jack l0 constructed in the aforementioned manner, attention is now directed to the way in which it operates. Specifically, attention is directed to FIG. 3, which shows the jack in its lowered or load releasing position. As can be seen there, the lower links or channels 34 and 34a, the link pairs 50 and 50a, and the upper links or channels 60 and 60a are positioned so as to extend in a substantially horizontal direction. In order to raise the load lifting element 22, which in turn raises a load (not shown) supported thereby, the screw element 96 is rotated about its longitudinal axis, by utilization of, for example, a wrench or other suitable tool which cooperates with the screw head 98. As the screw element rotates in this manner, the threaded nut 104 and attached bracket 82 are driven along the body portion 94 of the screw element towards the screw head 98. This, in turn, causes the lower link or channel 34a to pivot in a clockwise manner, as viewed in FIGS. 11 and 3, about the axis of pivot pin 44a. This, of course, causes the lower link or channel 34 to simultaneously pivot, in a counterclockwise manner, about the pivot pin 44. It should be noted that as lower link or channel 34 pivots in this manner, the

entire screw element 96 along with bracket 80 are shifted to the left, in an arcuate fashion, as viewed in FIGS. 1 and 3.

As the lower links or channels 34 and 34a pivot in the aforementioned manner, the lower ends of the linked pairs 50 and 50a move towards each other in a scissors fashion, while the upper ends thereof do the same. In order to do this, of course, the links or connecting arms 52 and 54 of linked pair 50 and links or connecting arms 52a and 54a of linked pair 50a must pivot about the pivot pin 74.

As the top ends of linked pairs 50 and 50a move together, the bottom ends of upper links or channels 60 and 60a will be forced from their substantially horizontal position to a substantially vertical position adjacent each, as viewed in FIG. 1, the upper ends of the upper channels being pivoted about the pivot pin 76. In this manner, the load lifting element 22 is vertically moved upwardly from its load releasing position to a load lifting position, as viewed in FIG. 1.

Moving the load lifting element from its load lifting position to its load releasing position is accomplished merely by rotating the screw element 96 in an opposite direction which, of course, causes the lower link assembly 14, intermediate link assembly 16, and upper link assembly 18 to move back to their substantially horizontal positions.

While a particular embodiment of the invention has been shown, it should be understood, of course, that the invention is not limited thereto, since many modifications may be made. It is, therefore, contemplated to cover by the present application any such modifications as fall within the true spirit and scope of the appended claims.

The invention is claimed as follows:

I. A scissors jack comprising: support means including a substantially flat horizontal base portion, side portions formed with and extending upwardly from said base portion and flange portions also formed with and extending upwardly from said base portion in confronting relationship with and spaced apart from said side portions; first and second lower elongated links mounted at common lower ends to and between confronting side and flange portions for pivotal movement towards and away from each other; a load lifting element; linking means interconnecting said load lifting element and the upper ends of said lower links for moving said load lifting element in response to the movement of said lower links; and drive means for moving said lower links and therefore said load lifting element.

2. A scissors jack according to claim 1 wherein a longitudinal edge of each of said lower links is formed with flange means for adding strength to said link.

3. A scissors jack according to claim 1 wherein said base portion is an integral unit constructed of stamped sheet metal.

4. A scissors jack according to claim 3 wherein the flange portions of said support means are formed from a part of said base portion.

5. A scissors jack according to claim 1 wherein the base portion of said support means includes a plurality of downwardly extending feet for supporting said support means, said feet being formed from said base portlon.

6. A scissors jack according to claim 1 wherein said first and second lower links are identical.

7. A scissors jack according to claim 1 wherein each of said lower links includes spaced apart and confronting elongated sides joined together at common longitudinal edges by an elongated joining flange, the lower end of each of said sides being mounted to and between a corresponding side portion and flange portion of said support means for said pivotal movement.

8. A scissors jack according to claim 7 wherein a free longitudinal edge of each of the side portions of said lower links includes an outwardly flaring portion for adding strength to said links.

9. A scissors jack comprising: a load lifting element; first and second substantially U-shaped elongated identical upper links, the legs of said upper links being mounted at their upper ends to said load lifting element for pivotal movement towards and away from each other for vertically moving said load lifting element; support means including a substantially horizontal base portion, side portions formed with and extending upwardly from said base portion and flange portions also formed with and extending upwardly from said base portion in confronting relationship and spaced apart from said side portions; first and second substantially U-shaped and elongated identical lower links, the leg portions of each of said lower links being mounted at their lower ends to and between corresponding confronting side and flange portions of said supporting means for pivotal movement towards and away from each other; intermediate linking means interconnecting the lower ends of said upper links and the upper ends of said lower links for pivotally moving said upper links in response to the pivotal movement of said lower links; and driving means for pivotally moving said lower links and therefore said upper links and said load lifting element, said driving means including a first apertured support bracket mounted between said first lower link and said linking means, a second apertured support bracket mounted between the lower ends of said linking means and elongated screw means mounted for rotation through the apertures of said brackets and cooperating therewith for pivotally moving said first and second lower links upon longitudinal rotation of said screw means.

10. A scissors jack according to claim 9 wherein said load lifting element, said support means, said upper links and said lower links are integral units each of which is constructed from stamped sheet metal. 

1. A scissors jack comprising: support means including a substantially flat horizontal base portion, side portions formed with and extending upwardly from said base portion and flange portions also formed with and extending upwardly from said base portion in confronting relationship with and spaced apart from said side portions; first and second lower elongated links mounted at common lower ends to and between confronting side and flange portions for pivotal movement towards and away from each other; a load lifting element; linking means interconnecting said load lifting element and the upper ends of said lower links for moving said load lifting element in response to the movement of said lower links; and drive means for moving said lower links and therefore said load lifting element.
 2. A scissors jack according to claim 1 wherein a longitudinal edge of each of said lower links is formed with flange means for adding strength to said link.
 3. A scissors jack according to claim 1 wherein said base portion is an integral unit constructed of stamped sheet metal.
 4. A scissors jack according to claim 3 wherein the flange portions of said support means are formed from a part of said base portion.
 5. A scissors jack according to claim 1 wherein the base portion of said support means includes a plurality of downwardly extending feet for supporting said support means, said feet being formed from said base portion.
 6. A scissors jack according to claim 1 wherein said first and second lower links are identical.
 7. A scissors jack according to claim 1 wherein each of said lower links includes spaced apart and confronting elongated sides joined together at common longitudinal edges by an elongated joining flange, the lower end of each of said sides being mounted to and between a corresponding side portion and flange portion of said support means for said pivotal movement.
 8. A scissors jack according to claim 7 wherein a free longitudinal edge of each of the side portions of said lower links includes an outwardly flaring portion for adding strength to said links.
 9. A scissors jack comprising: a load lifting element; first and second substantially U-shaped elongated identical upper links, the legs of said upper links being mounted at their upper ends to said load lifting element for pivotal movement towards and away from each other for vertically moving said load lifting element; support means including a substantially horizontal base portion, side portions formed with and extending upwardly from said base portion and flange portions also formed with and extending upwardly from said base portion in confronting relationship and spaced apart from said side portions; first and second substantially U-shaped and elongated identical lower links, the leg portions of each of said lower links being mounted at their lower ends to and between corresponding confronting side and flange portions of said supporting means for pivotal movement towards and away from each other; intermediate linking means interconnecting the lower ends of said upper links and the upper ends of said lower links for pivotally moving said upper links in response to the pivotal movement of said lower links; and driving means for pivotally moving said lower links and therefore said upper links and said load lifting element, said driving means including a first apertured support bracket mounted between said first lower link and said linking means, a second apertured support bracket mounted between the lower ends of said linking means and elongated screw means mounted for rotation through the apertures of said brackets and cooperating therewith for pivotally moving said first and second lower links upon longitudinal rotation of said screw means.
 10. A scissors jack according to claim 9 wherein said load lifting element, said support means, said upper links and said lower links are integral units each of which is constructed from stamped sheet metal. 